A new study offers a glimmer of hope in the grim fight against the coronavirus: Nearly everyone who has had the disease — regardless of age, sex or severity of illness — makes antibodies to the virus.

The study, posted online on Tuesday but not yet reviewed by experts, also hints that anyone who has recovered from infection may safely return to work — although it is unclear how long their protection might last.

“This is very good news,” said Angela Rasmussen, a virologist at Columbia University in New York who was not involved with the work.